Clay or Play dough (have a second choice in case others choose it first)

According to the apple-or-coin test, used in the Middle Ages, children should start school when they are mature enough for the delayed gratification and abstract reasoning involved in choosing money over fruit. In 15th- and 16th-century Germany, parents were told to send their children to school when the children started to act “rational.” And in contemporary America, children are deemed eligible to enter kindergarten according to an arbitrary date on the calendar known as the birthday cutoff — that is, when the state, or in some instances the school district, determines they are old enough. ~Elizabeth Weil